Potentially avoidable surgical complications may have contributed to the deaths of five cancer patients, an NHS Trust has revealed.

The five all died within a year following upper gastrointestinal (GI) surgery at Maidstone Hospital in Kent, run by Maidstone and Tunbridge Wells NHS Trust.

Upper GI surgery has been suspended and the trust is now sending patients requiring it to St Thomas' Hospital in central London instead.

The incidents have been referred to the General Medical Council (GMC), and the trust has conducted its own internal inquiry.

It said that "while members of staff have been held to account, their overall standard of practice does not support further sanctions".

The trust has apologised to the families affected and it has highlighted the need for improvements to be made.

Medical director Dr Paul Sigston said: "We are sorry that some patients did not receive the level of care and treatment that they should have due to potentially avoidable surgical complications.

"We are in contact with, and have apologised to, the families who have been affected and have been clear that we need to make improvements."

As part of its review, the trust commissioned an assessment of its upper GI cancer surgery by the Royal College of Surgeons last year.

It highlighted that the service had a higher-than-expected complication rate in 2012 and last year, resulting in longer post-operative recovery times for some patients.

In a statement, the trust said: "The trust's review has since established that while the outcomes for patients who had this surgery were within expected levels, including one and three years survival, surgical complications may have contributed to the deaths of five patients in its care during 2012/13.

"These were associated with the use of laparoscopic techniques and were potentially avoidable."

The arrangement with St Thomas' will continue for 12 months while the trust tries to improve its upper GI cancer surgery service.

Patients will still receive most of the upper GI intestinal cancer care locally, including chemotherapy, radiotherapy and initial surgical assessment.

Dr Sigston said: "Our first priority is to our patients and the actions we have taken will ensure the quality of care they receive is of the highest possible standard while improvements are made to address the findings of this review.

"There are important lessons for us here and we are working hard to improve the care we provide to patients."

The trust said that due to patient confidentiality the review will not be released. A spokesman said its recommendations will be issued after all the families involved have been spoken to.

Solicitor Sharon Lam, acting for the widow of a 51-year-old father of one who died days after surgery, said her client feels they were treated "like a human guinea pig".

Ms Lam said the man, who has not been named, had keyhole surgery to remove a tumour in his oesophagus last year and died from a haemorrhage five days after being discharged.

"Our main concern is that the deceased could have opted for a more conventional procedure, but this particular procedure was highly advocated by the surgeon," Ms Lam said.

"It was as if it was being sold to him, that he could have it done early and it would be carried out by a top surgeon.

"The patient was made to feel that they were quite lucky to have this surgery. Our client feels they have been treated like a human guinea pig to test the eligibility of this surgery.

"He was not told that it was a very new surgery. At no time was he offered the conventional surgery, and it all happened so quickly."

She added that the man should have had a good prospect of recovery, but instead his death has left his family traumatised.

The trust said that "for HR reasons" it was unable to disclose what action has been taken against members of staff following the five deaths.

A spokesman said: "As stated, the trust has separately carried out its own internal investigation and while members of staff have been held to account, their overall standard of practice does not support further sanctions.

"For HR reasons, the trust is unable to expand on this but can confirm that its surgeons are no longer carrying out upper gastrointestinal cancer surgery."

The complications which might have contributed to the five deaths "were not solely due to one specific and reoccurring theme", the spokesman said.

He added: "The types of complications were unusual for this type of surgery, however, and probably associated with laparoscopic techniques."

The trust has made the review available to the GMC but it will not be revealed publicly, the spokesman said.

He said: "The trust will be making the detailed recommendations of its review public once it has spoken to the families involved. It has made this promise to the families.

"The report in itself cannot be disclosed in its entirety, due to a combination of Data Protection Act limitations and other duties of confidentiality owed by this trust.

"However, in sharing the detailed recommendations, we seek to share as much of the review as we are able to make public at this time."

The Royal College of Surgeons (RCS) said it was continuing to monitor the trust's work in implementing the recommendations from its report.

An RCS spokesman said: "At the invitation of the trust, the Royal College of Surgeons carried out an invited review of the oesophageal and gastric cancer resection service in October 2013.

"At the end of our visit we provided immediate feedback about our patient safety concerns for the trust's medical director to address.

"Our final report, issued in December 2013, set out these concerns in detail and recommended the trust referred the situation to the Care Quality Commission (CQC) and GMC.

"The trust then confirmed this action had been taken and we continue to monitor the trust's work to implement the recommendations of our report.

"Our invited reviews enable expert teams, including a lay person representing the patient and public interest, to determine whether there is cause for concern about surgical practice and to make recommendations for improvement.